Catheter-associated urinary infections are the most common hospital-acquired infections and can be prevented by early catheter removal. This study evaluates tamsulosin to reduce the failure of early catheter removal has been studied in elderly women hospitalized for an acute condition and experiencing acute urinary retention: 448 women 75-year old or more without an anatomical or neurological cause of urinary retention will be randomized to a 6 days course of tamsulosin 0.4 mg or placebo. Catheter removal will be attempted after the third dose of tamsulosin and the need to replace another catheter within 72 hours will define a failed attempt.